Abstract

This article is for people that want to add an encrypted filespace to their Link Station. We will use the powerpc-hdhglan Link Station for our example.
EncFS is used to do this. This probably will work on any PPC link station. It may work on a MIPS Link station
but you'll have to compile the FUSE module yourself somehow.

Encryption Type : EncFS was chosen because of it's relative ease and speed of use. Loop-AES could be used as well, a good comparison is here: Encrypt filesystems with EncFS and Loop-AES , A client side encryption system like Truecrypt could be used from a windows client

Create an encrypted partition

place it in a shared directory if you want to access it as a file share using Samba.

encfs --public /mnt/locked /mnt/share/locked

/mnt/share here is a shared directory. /mnt/locked is where the encrypted bits will be stored and /mnt/share/locked is where the (de)crypted space will be mounted to. You will be prompted for the type of encryption that you want and for password creation. Look here for more details on using EncFS.

Access Permissions

You will have to chmod the created directory so everyone can access it

chmod og+rwx /mnt/share/locked/

Just beware that it takes a long time for files to be encrypted when you copy or move them into this directory, however you can use this directory like any other shared space with Samba. After files are placed in there they can be accessed pretty fast.

Unmount

You can unmount the partition at any time in which case the encrypted directory will end up appearing blank.

fusermount -u /mnt/share/locked

Remount

And remount it when you need it the same way you created it, this time you will just be prompted for the password you used when you created it.

encfs --public /mnt/locked /mnt/share/locked

What's the point?

What's the point of all this? Well you can create an encrypted file space that once mounted functions completely transparently as a shared directory. Once it is unmounted, either manually or automatically (when the system is shut down) the data will only exist in an encrypted form in the encrypted directory you specified. In this example in /mnt/locked , if your linkstation is stolen or lost, as soon as it is unplugged the data will no longer be accessible without the password. Even if someone cracks open the device and takes the hard drive out all they will be able to get is encrypted gibberish in that directory. However they would be able to figure out how MANY files you had in that directory and the SIZE of each file, as EncFS encypts each file individually, not the block device.

Keyfile and Security

The keyfile is stored in the encrypted directory /mnt/locked/.encfs5 you could store it externally (on a USB Key Drive for example) and move it to the proper location if you wanted even more security.